If you've ever uttered a saying along the lines of “My Very Educated Mother Just Served Us Nine Pizzas," then you probably learned a mnemonic device to help you remember the order of the planets in our solar system. After all, it's an easy way to remember the order of Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.

Of course, scientists then went and messed everything up by stripping Pluto of its status as a full-fledged planet. Maybe a new saying could be "My Very Educated Mother Just Served Us Nachos." Would that be the last time the saying would have to change? You never know. New scientific discoveries could bring a need to change it yet again.

For example, did you know that there's a planet between Mars and Jupiter? Wait a second, you may be thinking. My Very Educated Mother Just…nope, there's nothing else between Mother and Just. What are we talking about? Ceres, of course!

Ceres (pronounced “series") is a dwarfplanet that sits in the asteroidbelt between Mars and Jupiter. It's the largest object between those two planets, and it's also the largest object between the Sun and Pluto that had never been visited by a spacecraft.

That changed in March 2015, however, when NASA's Dawn spacecraft explored Ceres for the first time. Scientists hope to learn more about this dwarfplanet that was first discovered in 1801 — nearly 130 years before Pluto!

Like Pluto, Ceres is a dwarfplanet, which means that it's round and orbits the Sun but has not yet "cleared the neighborhood" of its orbit in space of other objects. In other words, Ceres' gravitational force isn't great enough to overpower other objects in its path—either by attracting or repelling them—as it orbits around the sun. In addition to Ceres and Pluto, the International Astronomical Union currently recognizes three other dwarf planets: Eris, Makemake, and Haumea. However, scientists believe that there could be hundreds more dwarf planets yet to be discovered.

Photographs from the Dawn spacecraft show that the surface of Ceres appears to be covered with craters that are like scars from the dwarfplanet's rough life in the asteroidbelt. Scientists speculate that Ceres may have been developing into a full-sized planet when Jupiter's formation halted its growth approximately 4.6 billion years ago. Studying Ceres may give scientists further insight into how the solar system formed.

So what will scientists discover when the Dawn spacecraft sends back data about Ceres? Some scientists believe Ceres is mainly made up of rock and ice with liquid water deep underground. Other scientists have speculated that the Dawn spacecraft will find a weird world of volcanoes that spew ice rather than lava with a thin frozen outer shell that conceals an ocean of mud that could harbor life. Hopefully, Dawn's exploration of Ceres will give scientists enough data to clarify their understanding of this mysterious dwarfplanet!

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Try It Out

Did you enjoy learning more about dwarf planets? Learn even more when you check out the following activities with a friend or family member:

Curious about what dwarf planet Ceres looks like? To see some images from space telescopes, check out the Ceres photo gallery What do you think? Does it look like a planet to you? Could it hold life? Share what you've learned with a friend or family member.

NASA's Dawn spacecraft is on a mission to study Ceres and Vesta in the asteroid belt. To learn more about Dawn's mission and see incredible photographs, check out the Dawn Mission page on NASA's site. Feel free to explore the site with a friend or family member. Make a list of at least five new facts that you learn from researching the site. Where do you think NASA should send a probe next?

Up for a challenge? Write a series of journal entries that tell the story of your pioneering manned mission to Ceres. How long did it take you to get there? What kind of spacecraft did you travel in? What did you find when you got to Ceres? Was there alien life on the dwarf planet? Use your imagination to spin a fascinating tale of what interstellar travel to a dwarf planet might be like!

Evelyn

Wonderopolis

May 14, 2015

Dear Evelyn,
Thanks for the compliment. We appreciate you being a supportive WONDER friend and visiting WONDERopolis! Flat Stanley is a WONDERful book series. While we don't have a WONDER specifically about Flat Stanley, we have many WONDERS about books, such as pop-up books, tunnel books, and how books are made. Check them out here! :)

lazer1423

Wonderopolis

May 12, 2015

Good afternoon, lazer1423! The International Astronomical Union currently recognizes three other dwarf planets: Eris, Makemake, and Haumea. Also, scientists believe that there could be hundreds more dwarf planets yet to be discovered. Always keep WONDERing! :)

Nehemiah Alvarez

Wonderopolis

May 12, 2015

Hello, Nehemiah Alvarez! We're glad you liked today's WOD! Maybe you can continue researching dwarf planets at your library. There are also many other WONDERS about planets on WONDERopolis. We hope this helps! :)